Amniotic Fluid Embolism – Symptoms, Causes and Treatment

There are many potential dangers to mother and unborn child that can arise during pregnancy. Some are well know, like an ectopic pregnancy or pre-eclampsia. However, there are several lesser known pregnancy-related conditions that can be serious. One such conditions is amniotic fluid embolism which can be life threatening condition. Worldwide this condition is considered to be the fifth cause of maternal mortality.

What is amniotic fluid embolism?

Amniotic fluid protects the developing baby in the uterus during pregnancy. In amniotic fluid embolism, this fluid along with fetal material like hair enters the mother’s blood stream. Upon entering the mother’s circulation, the immune system responds to the presence of this foreign material. It leads to an inflammatory reaction and may result in abnormal blood clotting which can then affect normal blood flow.

Although less common as a cause of pregnancy-related death these days, amniotic fluid embolism is still a serious condition to the mother in particular. This condition usually occurs during childbirth or immediately after giving birth. However, there is discrepancy regarding the incidence and mortality rates of amniotic fluid embolism due to difficulty in diagnosis. Amniotic fluid embolism requires immediate medical attention otherwise it could lead to a fatal outcome.

Signs and Symptoms

The symptoms of amniotic fluid embolism develop suddenly and progress rapidly. The presenting symptoms can be divided into two phases. In the first phase the patient experiences breathing difficulty (dyspnea) and a drop in blood pressure (hypotension). The lower blood oxygen levels and the impaired blood supply to heart can cause heart failure which further restricts blood flow throughout the body. This may be seen as an altered mental status, confusion and even loss of consciousness as the oxygen supply to the brain is insufficient.

In the past, the mortality rate with amniotic fluid embolism was about 60% to 80%. However, with modern treatment options the mortality rate has reduced drastically. In other words, less women die from amniotic fluid embolism these days than they did in the past. This is largely dependent on the availability of medical treatment. Although most patients succumb in the first phase, many do progress to the second phase. In this phase the most common symptoms include shivering, coughing, vomiting and bleeding (hemorrhagic symptoms).

Excessive bleeding leads to a loss of clotting factors. These are the chemicals that helps the body seal breaks in the blood vessels by forming clots. In amniotic fluid embolism, the blood can lose the ability to clot. Ultimately it can result in a collapse of the cardiovascular system and this can progress to death. Amniotic fluid embolism may lead to a number of complications like permanent brain damage due to reduced oxygen supply to the brain.

Death from amniotic fluid embolism is more likely to occur in developing nations and remote areas where the lack of medical care can lead to complications. Even in developed countries, amniotic fluid embolism can lead to death if this condition arises and there is a lack of suitable medical facilities. As many as 1 in 10 cases of pregnancy-related deaths in developed countries are due to amniotic fluid embolism.

Causes of Amniotic Fluid Embolism

The fetus is surrounded by amniotic fluid with the placenta allowing for substances to cross between the mother and developing baby. Nutrients, gases and wastes can pass from the baby’s circulation to the mother’s circulation and vice versa. It ensures that the baby can develop while depending on the mother’s body to supply all the necessary nutrients and oxygen as well as remove wastes and carbon dioxide.

However, the blood of the mother and unborn child are kept separate. In an amniotic fluid embolism the amniotic fluid gains entry into the mother’s blood supply. The fluid may also contain fetal cells and hair. This occurs accidentally during childbirth or immediately after giving birth. The exact underlying cause of amniotic fluid embolism is not known but some women are at a greater risk than others.

What happens in amniotic fluid embolism?

Following entry of these foreign material into the mother’s circulation, the different components of the amniotic fluid stimulate an inflammatory reaction in the mother’s body. This results in the clotting of blood in the mother’s body. This clotting hampers the circulation of blood and therefore the distribution of oxygen throughout the body. If the condition progresses without medical intervention, it can lead to death.

Although in most of the pregnant women the amniotic fluid may enter the mother’s body, it rarely leads to amniotic fluid embolism. There are three prerequisites for entry of amniotic fluid in the maternal circulation; these are rupture of the membrane containing the amniotic fluid in the uterus, rupture of uterine or cervical veins and a pressure gradient between the uterus and veins.

Risk Factors

There are number of factors which increases the risk of suffering from amniotic fluid embolism. These include:

Advanced maternal age usually older than 35 years.

Abnormality in the placenta like placenta previa or placental abruption.

Preeclampsia.

Caesarean section or other operative procedures.

Certain genetic factors.

Pregnant women with one or more of these risk factors may develop amniotic fluid embolism. However, it will definitively affect every pregnant women who is in a high risk group. Similarly, some women who do develop amniotic fluid embolism may have none of these risk factors present.

Treatment of Amniotic Fluid Embolism

Amniotic fluid embolism should be considered a medical emergency that requires immediate treatment and appropriate management. The approach to treatment depends on several factors but focuses on restoring normal blood circulation and adequate oxygen distribution. It may involve a combination of supportive measures, drug therapy and sometimes even surgical intervention.

The treatment measures includes the use of certain drugs, oxygen administration and a blood transfusion if necessary. Although the mother is at risk since the condition arises during and immediately after childbirth, sometimes the baby may also be at risk. If amniotic fluid embolism occurs before birth of the baby, the a Caesarean section is advisable so as to reduce the risk to the baby.